1. Field of the Invention
The present invention relates generally to the field of computer based multimedia authoring tools, and more particularly to authoring tools for manipulating screen objects during the authoring of multimedia art.
2. Description of the Background Art
A multimedia art work typically consists of interrelated graphic, sound, and text objects, which illustrate and convey the subject matter of work. The multimedia objects are typically combined with varying visual and audio effects that enhance the impact of the presentation. Motion effects are particularly important, as they can be used to convey complex relationships between objects over time, and highlight the content of the presentation. Associated with the motion or position of an object can be a visual effect, such a wipe, fade, reveal, and the like. These visual effects further enhance the motion or positioning of the object by focusing the viewer's attention on the object, and by providing a means for smoothly integrating various types of objects into a coordinated ensemble of images and text. Sound effects further enchance the multimedia art work, for example, associating a recording of an airplane's engine with a graphic image of such an engine.
Since a multimedia art work typically provides a changing array of images and objects, each object has an associated time duration that can be divided into any number of time segments. There are typically at least three main time segments: the appearance, or entry, of the object on the display, the hold or stationary positioning of the object, and the disappearance, or exit, of the object from the display. During its entry and exit on the display, the motion of the object needs to be controlled, generally with respect to a common reference, such as the boundary of the display. Thus, an object can, from a given point of entry on the display, move downward toward the bottom of the display, hold in a selected position on the display, and then exit by moving toward the right boundary. Likewise, associated with each time segment can be a visual effect. Thus, an object can enter from the left of the display, moving toward the center while fading in, then hold in the middle of the display while blinking, and then move toward the right of the display while having a vertical wipe applied. Such combinations of movement and visual effect can be applied to many different objects that are included in the multimedia art, resulting in a richly textured and visually dynamic work.
Accordingly, the complex combination of motion, direction, position, and visual effect must be coordinated by the multimedia artist to develop high quality multimedia art. Where there are various possible directions of movements, and numerous visual effects that can be applied, the artist needs a design tool that allows the rapid and flexible application of both motion and visual effects for a given multimedia object. Since the motion and visual effects are related to the time segments of an object's duration, it is desirable for a design tool allow the effects to be applied with respect to each time segment of an object's duration. Further, there is a need to control the beginning, or cue, and duration of sound effects associated with the object.
Conventional approaches to controlling the motion, visual, and audio effects of multimedia objects have generally not provided for the coordinated control of these effects. Typically, various different menus, screen prompts and other interface elements must be accessed and manipulated in specific sequences merely to apply a single effect to an object. For example, where a menu is used to set a motion effect for an object, the use must activate the menu, and then choose from a list of text items the name of the desired effect. The absence of a visual reference for the effect impairs the ease of use of the menu, and since the menu disappears after use, the artist typically has no way of determining the current motion direction setting other than selecting the menu again. Since there are at least six settings of interest (the motion direction and visual effect for each of the entry, hold and exit time segments), separating the controls for all of these functions into different menus means that the artist is unable to determine in a single glance, the settings for all of the effects, but rather, must activate numerous different menus.
Another problem is that the means for effecting each type of effect are unrelated, such as different menus or other interface elements, each for applying only a single type of effect, unrelated generally to a time segment, or another effect. Thus the artist must select from one menu or dialog box to apply a visual effect, and another unrelated menu to apply a motion effect to the same object. Because of the structural limitations of menus, there is no way for the menu to associate its effects with a particular time segment of the object's duration. This lack of integration means there is typically little direct relationship between applying an effect to an object and controlling the time segment to which the visual effect or motion effect applies.
It is desirable therefore to provide a multimedia art design tool that effectively integrates the application of motion and visual effects with the various time segments of an object's duration on the display.